在非UI线程中更改UI（Delphi使用隐藏窗口来处理，QT使用信号槽）

在Delphi里我记得是使用TThread.Synchronize(TThreadMethod)，原理是利用了一个隐藏窗口来处理。

在QT Debug模式一下，碰到了同样的问题，显示错误：

cannot send events to objects owned by a different thread

解决方案是使用信号槽，就是在线程里不断的发信号，UI线程的槽函数不断的接受信号并做处理：

So as a solution I would propose the following:

• Define a signal in your PaintThread class
• connect this signal to the paint() slot in QWidget subclass
• Emit it in the run() function

参考：http://stackoverflow.com/questions/9018434/qthread-doesnt-work-well

或者使用：

int ThreadTest::showProgress(int percent, void *pContext)
{
// instead of: someOtherQObject->updateProgress(percent);
QMetaObject::invokeMethod(someOtherQObject, // obj
SLOT(updateProgress(int)), // member
Qt::QueuedConnection, // connection type
Q_ARG(int, percent)); // val1

//qDebug() << "Progress: " << QString::number(percent);
return 0;
}

https://forum.qt.io/topic/9119/solved-how-can-i-evade-the-error-cannot-send-events-to-objects-owned-by-a-different-thread/4